Seen photos of this online before and just happpened to spot it on our little trip around Norfolk on Sunday, it would have been rude not to stop and have a quick look. The weather was great so made for some good photos.
This is an old ROC post that has been converted for use as part of the Walsey Hills nature reserve. It has been uncovered with a door and window fitted. The Orlit has been converted into a bird watching hut.